Dry cleaning method



May 21, 1968 H. S. GILBERT DRY CLEAN I NG METHOD Filed April 27, 1964 Va/ve INVENTOR. Herman 6. Gilber/ United States Patent 3,384,445 DRY CLEANING METHOD Herman S. Gilbert, Angleton, Tex., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed Apr. 27, 1964, Ser. No. 362,899 6 Claims. (Cl. 8-142) ABSTRACT OF THE DISCLOSURE This invention relates to a method of dry cleaning fabrics wherein vaporized solvent from the cleaning operation is extracted, condensed, and stored for use as'a solvent rinse before the final solvent extraction and fabric drying part of the cleaning cycle.

BACKGROUND OF THE INVENTION This invention relates to an apparatus and method for cleaning fabrics by dry cleaning, and particularly to coin operated dry cleaning apparatus and a method of operating such apparatus.

In so-called dry cleaning operations clothes or other fabrics are usually cleaned by agitating them while passing a non-aqueous solvent through them which often contains a detergent or soap and then extracting the solvent.

The removed soils are either suspended or dissolved in the solvent used in the cleaning operation. Suspended materials are removed from the solvent by filtering, while dissolved soils are removed either by adsorption on activated carbon, by using so-called sweetener powders to change the fatty acids to soaps or by distilling the solvent.

While distilling the solvent is a desirable way to separate non-volatile matter from the solvent, it is not really practical from an economic standpoint to distill all the solvent used between each cleaning operation.

In the most widely used types of coin operated dry cleaning equipment, for example, up to 55 gallons or even more of solvent is used during each cycle of operation. It is too expensive in such a highly competitive business to distill all of the solvent which is used during each cycle of operation. As a substitute it is known to distill a small fraction of the solvent used during each cycle on an indiscriminate basis to remove at least part of the non-volatile materials from the solvent and slow the build up of non-volatile materials in the solvent.

However, the amount of non-volatile material which is in the solvent continues to build up and often causes the supposedly cleaned fabric to have a bad or unpleasant odor.

Accordingly, a principal object of this invention is to provide an improved, economical method and apparatus for reducing the amount of non-volatile materials in fabric which is dry cleaned.

Another object of this invention is to provide an improved, simple to operate, economical apparatus and method for removing non-volatile materials from dry cleaned fabrics.

In accoradnce with this invention there is provided means and a method for condensing the solvent vapors which are removed from the wash wheel assembly during the extraction part of the cleaning cycle, storing the condensed solvent vapor and then using it as a final rinse for the fabric being cleaned. Thus, the solvent used in the final rinse is free of non-volatile material when it is applied. It is essential, however, that the rinsing with distilled solvent be accomplished immediately before or during the final spin extraction and while the clothing is still saturated with solvent, but prior to the drying cycle in the machine. The rinse solvent therefore sharply re- 3,384,445 Patented May 21, 1968 duces the amount of non-volatile material remaining in the fabric being cleaned, with the result that the cleaned fabric is both cleaner and has a better odor than if nondistilled solvent were used in the rinsing operation.

The invention, as well as additional objects and advantages thereof, will best be understood when the following detailed description is read in connection with the accompanying drawing, in which:

The single figure shows, in simplified diagrammatical form, apparatus in accordance with this invention.

Referring to the drawing, there is shown dry cleaning apparatus, indicated generally by the numeral 10, which comprises a base tank 12, a wash wheel assembly 14 including an outer housing 16 and rotatable wash wheel 18, a filter 20, pump 22, condenser 24, heater 26, blower 28, solvent reservoir 30, and solenoid controlled valves 32, 34.

The filter 20 is coupled to a spray nozzle 42 within the housing 16 of the wash wheel assembly 14 by a hollow tube 44. The filter 20 is also coupled to the base tank 12 through hollow conduits 46, 48 and the pump 22.

A drain tube 50 having a valve 36 incorporated therein is coupled between the base tank 12 and the wash wheel assembly 14 and provides means for draining solvent from within the housing 16 of the wash wheel assembly.

A gas and solevnt vapor circulation system is provided which includes the condenser 24, heater 26, solvent reservoir 30, valves 32, 34, and interconnecting tubing 56, 58, 60, 62, 64.

The tubing 56, blower 28 and tubing 58 connect the wash wheel housing 16 to the input 66 of the condenser 24. The tubing 60 extends from within the condenser 24 through the heater 26 and back into the wash wheel housing 16. The condensate output end 68 of the condenser 24 is coupled through the line 62 and valve 32 to the condensed solvent reservoir 30. The reservoir 30 is coupled through the line 64 and valve 34 to the upper part of the wash wheel housing 16. The valve controller 38 coupled, as at A and B, to the solenoid valves 32, 34, actuates the valves 36, 38 to provide a flow of solvent into and out of reservoir 30 at appropriate times during the machine cycle.

In operation, as filtered solvent is pumped by means of the pump 22 through the nozzle 42 and onto the load of fabric (not shown) which is being tumbled by the rotating wash wheel 18, the solvent which has passed through or impinged on the fabric being cleaned usually returns from the housing 16 to the base tank 12 through the line 50 and valve 36. The valve 36 may be partly or completely closed for at least part of the wash cycle in order to keep a solvent inventory in the wash wheel.

Following the wash cycle, the wash wheel 18 is rotated at a rapid rate as is well known in the art to extract the solvent from the fabric load. Simultaneously, gas and solvent vapors are drawn from the housing 16 by means of the blower 28 through the lines 56, 58. The vapors and gas from the line 58 are passed through the condenser 24, the solvent liquefying into droplets and dropping through the tube 62 and thence into the solvent reservoir 30, the valve 34 being closed and the valve 32 being open.

The uncondensed gas and vapors leave the condenser 24 through the line 60, passing through the heater 26 before returning to the wash wheel assembly 14, as is well known in the dry cleaning art. As the heated air reenters the wash wheel housing 16 additional solvent in the fabric is vaporized and withdrawn from the wash wheel assembly through the line 56 as described above.

After the extraction operation, the distilled solvent from the solvent reservoir is dispersed, by opening the valve 34, for example, into the wash wheel 18 and onto the fabric being cleaned. This distilled solvent acts as a rinse for the fabric being cleaned, thus diluting the amount of non-volatile material which remained in the fabric after the first extraction operation.

The amount of distilled solvent which is available for use as a rinse may be increased by operating the blower 28 and condenser 24 throughout the washing cycle as well as during the solvent extraction or spinning cycles of the cleaning operation.

As illustrated in the drawing, a direct gravity fiow of the distilled solvent in the reservoir 30 to the wash wheel 18 occurs. The rapid spinning of the wash wheel will provide about the same effect as though the solvent were sprayed from the nozzle 42.

However, the solvent reservoir 30 (about 1 gallon capacity) may, if desired be located below the wash wheel (or elsewhere) and the rinse solvent be pumped into the wash wheel by means of a separate pump and a suitable nozzle.

This invention provides an economical to construct and operate means and method of substantially reducing the non-volatile material remaining in fabric after it is dry cleaned.

What is claimed is:

1. In a method of dry cleaning wherein fabrics are cleaned by imparting motion to said fabric while contacting said fabric with liquid solvent, extracting a substantial amount of said solvent from said fabric by centrifugal force, heating the remaining solvent to vaporize it, flowing said vapor away from said fabrics to dry said fabrics, then followed by aerating said fabrics, the steps of condensing vapors from said solvent which contacts said fabric and accumulating a predetermined volume of condensed solvent, and then utilizing said condensed solvent to rinse said fabric before finally extracting the solvent from the fabric by centrifugal force, heating the solvent and flowing vaporized solvent away from the fabric.

2. In a method of dry cleaning wherein fabrics are cleaned by tumbling said fabric while contacting said fabric with liquid solvent, extracting a substantial amount of said solvent from said fabric by centrifugal force, heating the remaining solvent to vaporize it, flowing said vapor away from said fabrics to dry said fabrics, then followed by aerating said fabrics, the steps of condensing solvent vapors which are flowed away from said fabric and accumulating a predetermined volume of condensed solvent, and then applying said condensed solvent to said fabric as a rinse before finally extracting the solvent from the fabric by centrifugal force, heating the solvent and flowing vaporized solvent away from the fabric.

3. A method in accordance with claim 1, wherein said fabric is aerated after it is dried.

4. A method in accordance with claim 1, wherein said solvent vapors are condensed and accumulated during the entire cleaning, and solvent extraction and drying cycles of the dry cleaning operation.

' 5. A method in accordance with claim 1, wherein said solvent vapors are condensed and accumulated only during the solvent extraction and drying cycles of the dry cleaning operation.

6. A method of dry cleaning fabrics with a liquid nonaqueous solvent which comprises contracting said fabrics with a quantity of said solvent at least sufficient to saturate said fabric, agitating said saturated fabric, extracting a substantial amount of said solvent from said fabric by centrifugal force, condensing vapors from the solvent which contacts said fabric and accumulating a predetermined volume thereof, utilizing said condensed solvent to rinse said fabric, and finally heating said solvent and flowing vaporized solvent away from the fabric until said fabric is substantially solvent free, and then aerating said fabric.

References Cited UNITED STATES PATENTS 2,831,332 4/1958 Ross 8l42 2,979,375 4/1961 Kircher 3-142 FOREIGN PATENTS 514,126 6/1955 Canada.

LEON D. ROSDOL, Primary Examiner. MAYER WEINBLATT, Examiner. 

